flows that demonstrate how to create a connected object, control a Raspberry Pi, read from a sensor, and send an email or text message when a threshold is reached. Node-RED can be used to create applications that interact with physical devices, web services, and APIs to process and act on data in real-time.
The Express.js router is used to create modular, mountable route handlers. It provides a way for organizing routes and sharing route logic across multiple files.
For example, if you have a website with multiple pages, you can use the Express.js router to create a separate file for each page and mount them all in the main server file.
const express = require(‘express’);
const router = express.Router();
// Home page
router.get(‘/’, (req, res) => {
res.render(‘home’);
});
// About page
router.get(‘/about’, (req, res) => {
res.render(‘about’);
});
// Mount the router in the main server file
app.use(‘/’, router);
Express.js is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs. It has been called the de facto standard server framework for Node.js.
Express.js works by providing a set of features that simplify the process of creating a web application. It provides a robust set of features for creating web and mobile applications, including: routing, middleware, view system, and more.
Example:
// import express module
const express = require(‘express’);
// create an express application
const app = express();
// define a route
app.get(‘/’, (req, res) => {
res.send(‘Hello World!’);
});
// start the server
app.listen(3000, () => {
console.log(‘Server is listening on port 3000’);
});
Flask is a web framework for Python. It is a micro web framework that provides a basic structure for web applications. Flask is a popular choice for web development as it is lightweight and provides a lot of flexibility.
Example:
from flask import Flask
app = Flask(__name__)
@app.route(“/”)
def hello():
return “Hello World!”
if __name__ == “__main__”:
app.run()
1. Fast and minimal: Express.js is a lightweight and fast web framework, which makes it perfect for building efficient and scalable web applications. It has a minimalistic approach and provides just the essential features needed for web development.
2. Routing: Express.js provides a robust set of features for routing requests. It supports dynamic routing, which allows you to define routes with variables and wildcards. For example, you can create a route for a specific user profile page like this:
app.get(‘/user/:username’, (req, res) => {
// Retrieve user profile data
});
3. Middleware: Express.js provides a powerful set of middleware functions, which are functions that are executed before a request is handled. These functions can be used to modify the request or response, authenticate requests, and perform other tasks. For example, you can use a middleware function to validate user input before processing the request.
4. Templating: Express.js supports templating engines, which allow you to render dynamic HTML pages based on data from the server. This makes it easy to create dynamic web pages with dynamic content. For example, you can use a templating engine to render a list of products with images and descriptions.
5. Database integration: Express.js makes it easy to integrate with databases. It supports popular databases such as MongoDB and MySQL, which makes it easy to store and retrieve data from the database. For example, you can use Express.js to retrieve a list of products from a MongoDB database and render them in a web page.
Vaibhav Kothia